implement SI units for distance / speed measurement, closes #2496

data/language/english_uk.txt

@@ -3921,6 +3921,8 @@ STR_5579    :Window scale factor:
 STR_5580    :Czech koruna (Kc)
 STR_5581    :Show FPS
 STR_5582    :Trap mouse cursor in window
+STR_5583    :{COMMA16}ms{POWERNEGATIVEONE}
+STR_5584    :SI
 
 #####################
 # Rides/attractions #

distribution/changelog.txt

@@ -2,6 +2,7 @@
 ------------------------------------------------------------------------
 - Feature: Add displaying of frames per second (FPS).
 - Feature: Changing the number of trains no longer requires retesting.
+- Feature: Add SI units as a new measurement system for distance / speed.
 - Fix: [#2126] Ferris Wheels set to "backward rotation" stop working (original
 bug)
 - Fix: [#2449] Turning off Day/Night Circle while it is night doesn't reset back to day

src/config.c

@@ -104,6 +104,7 @@ config_enum_definition _screenShotFormatEnum[] = {
 config_enum_definition _measurementFormatEnum[] = {
 	{ "IMPERIAL", MEASUREMENT_FORMAT_IMPERIAL },
 	{ "METRIC", MEASUREMENT_FORMAT_METRIC },
+	{ "SI", MEASUREMENT_FORMAT_SI },
 	END_OF_ENUM
 };
 

src/config.h

@@ -94,7 +94,8 @@ enum {
 
 enum {
 	MEASUREMENT_FORMAT_IMPERIAL,
-	MEASUREMENT_FORMAT_METRIC
+	MEASUREMENT_FORMAT_METRIC,
+	MEASUREMENT_FORMAT_SI
 };
 
 enum {

src/localisation/localisation.c

@@ -450,11 +450,20 @@ void format_length(char **dest, sint16 value)
 
 void format_velocity(char **dest, uint16 value)
 {
-	rct_string_id stringId = 2734;
+	rct_string_id stringId;
 
-	if (gConfigGeneral.measurement_format == MEASUREMENT_FORMAT_METRIC) {
+	switch (gConfigGeneral.measurement_format) {
+	default:
+		stringId = STR_UNIT_SUFFIX_MILES_PER_HOUR;
+		break;
+	case MEASUREMENT_FORMAT_METRIC:
 		value = mph_to_kmph(value);
-		stringId++;
+		stringId = STR_UNIT_SUFFIX_KILOMETRES_PER_HOUR;
+		break;
+	case MEASUREMENT_FORMAT_SI:
+		value = mph_to_mps(value);
+		stringId = STR_UNIT_SUFFIX_METRES_PER_SECOND;
+		break;
 	}
 
 	uint16 *argRef = &value;

src/localisation/string_ids.h

@@ -1407,6 +1407,11 @@ enum {
 	STR_SAVE_EVERY_HOUR = 2705,
 	STR_SAVE_NEVER = 2706,
 
+	STR_UNIT_SUFFIX_FEET = 2732,
+	STR_UNIT_SUFFIX_METRES = 2733,
+	STR_UNIT_SUFFIX_MILES_PER_HOUR = 2734,
+	STR_UNIT_SUFFIX_KILOMETRES_PER_HOUR = 2735,
+
 	STR_DATE_FORMAT_DMY = 2737,
 
 	STR_ROLLERCOASTER_TYCOON_1_DROPDOWN = 2740,
@@ -2182,6 +2187,9 @@ enum {
 
 	STR_TRAP_MOUSE = 5582,
 
+	STR_UNIT_SUFFIX_METRES_PER_SECOND = 5583,
+	STR_SI = 5584,
+
 	// Have to include resource strings (from scenarios and objects) for the time being now that language is partially working
 	STR_COUNT = 32768
 };

src/util/util.c

@@ -40,7 +40,13 @@ int mph_to_kmph(int mph)
 {
 	// 1 mph = 1.60934 kmph
 	// RCT2 approximates as 1.609375
-	return (mph * 1648) / 1024;
+	return (mph * 1648) >> 10;
+}
+
+int mph_to_mps(int mph)
+{
+	// 1 mph = 0.44704 m/s
+	return (mph * 58594) >> 17;
 }
 
 bool filename_valid_characters(const utf8 *filename)

src/util/util.h

@@ -26,6 +26,7 @@
 int squaredmetres_to_squaredfeet(int squaredMetres);
 int metres_to_feet(int metres);
 int mph_to_kmph(int mph);
+int mph_to_mps(int mph);
 
 bool filename_valid_characters(const utf8 *filename);
 

src/windows/options.c

@@ -830,10 +830,12 @@ static void window_options_mousedown(int widgetIndex, rct_window*w, rct_widget*
 		case WIDX_DISTANCE_DROPDOWN:
 			gDropdownItemsFormat[0] = 1142;
 			gDropdownItemsFormat[1] = 1142;
+			gDropdownItemsFormat[2] = 1142;
 			gDropdownItemsArgs[0] = STR_IMPERIAL;
 			gDropdownItemsArgs[1] = STR_METRIC;
+			gDropdownItemsArgs[2] = STR_SI;
 
-			window_options_show_dropdown(w, widget, 2);
+			window_options_show_dropdown(w, widget, 3);
 
 			dropdown_set_checked(gConfigGeneral.measurement_format, true);
 			break;
@@ -1225,8 +1227,17 @@ static void window_options_invalidate(rct_window *w)
 		// currency: pounds, dollars, etc. (10 total)
 		RCT2_GLOBAL(0x013CE952 + 12, uint16) = CurrencyDescriptors[gConfigGeneral.currency_format].stringId;
 
-		// distance: metric/imperial
+		// distance: metric / imperial / si
-		RCT2_GLOBAL(0x013CE952 + 14, uint16) = STR_IMPERIAL + gConfigGeneral.measurement_format;
+		{
+			rct_string_id stringId;
+			switch (gConfigGeneral.measurement_format) {
+			default:
+			case MEASUREMENT_FORMAT_IMPERIAL: stringId = STR_IMPERIAL; break;
+			case MEASUREMENT_FORMAT_METRIC: stringId = STR_METRIC; break;
+			case MEASUREMENT_FORMAT_SI: stringId = STR_SI; break;
+			}
+			RCT2_GLOBAL(0x013CE952 + 14, uint16) = stringId;
+		}
 
 		// temperature: celsius/fahrenheit
 		RCT2_GLOBAL(0x013CE952 + 20, uint16) = STR_CELSIUS + gConfigGeneral.temperature_format;

src/windows/park.c

@@ -1585,7 +1585,7 @@ static void window_park_stats_paint(rct_window *w, rct_drawpixelinfo *dpi)
 	// Draw park size
 	parkSize = RCT2_GLOBAL(RCT2_ADDRESS_PARK_SIZE, uint16) * 10;
 	stringIndex = STR_PARK_SIZE_METRIC_LABEL;
-	if (!RCT2_GLOBAL(RCT2_ADDRESS_CONFIG_METRIC, uint8)) {
+	if (gConfigGeneral.measurement_format == MEASUREMENT_FORMAT_IMPERIAL) {
 		stringIndex = STR_PARK_SIZE_IMPERIAL_LABEL;
 		parkSize = squaredmetres_to_squaredfeet(parkSize);
 	}